Chemistry

Coordination Compounds

Question:

Explain on the basis of valence bond theory that  [Ni(CN)4]2-  ion with square planar structure is diamagnetic and the[Ni(CN)4]2- ion with tetrahedral geometry is paramagnetic.

Answer:


ncert-solutions-for-class-12-chemistry-coordination-compounds-5
ncert-solutions-for-class-12-chemistry-coordination-compounds-6

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Coordination Compounds

Q 1.

When 1 mol CrCl3.6H2O is treated with excess of AgNO3, 3 mol of AgCl are obtained. The formula of the complex is
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-6

Q 2.

Assertion (A): [Cr(H2O)6]Cl2 and [Fe(H2O)6]Cl2 are reducing in nature. Reason (R): Unpaired electrons are present in their J-orbitals.

Q 3.

Calculate the overall complex dissociation equilibrium constant for the  Cu(NH3)42+  ion, given that β4  for this complex is 2.1 x  1013.

Q 4.

What is meant by unidentate didentate and ambidentate ligands? Give two examples for each.

Q 5.

What is meant by the chelate effect? Give an example.

Q 6.

Which of the following options are correct for [Fe(CN)6]3- complex?
(a) d2sp3 hybridisation
(b) sp3d2  hybridisation
(c) Paramagnetic
(d) Diamagnetic

Q 7.

On the basis of crystal field theory explain why Co(III) forms paramagnetic octahedral complex with weak field ligands whereas it forms diamagnetic octahedral complex with strong field ligands.

Q 8.

[Fe(CN)6]4- and [Fe(H2O)6]2+ are of different cdlours in dilute solutions. Why?

Q 9.

Which of the following complexes show linkage isomerism?
(a) [CO(NH3)5(NO2)]2+  (b) [CO(H2O)5CO]3+
(c) [Cr(NH3)5SCN]2+  (d) [Fe(en)2Cl2]+

Q 10.

Magnetic moment of [MnCl4]2- is 5.92 BM. Explain giving reason.

Q 11.

In the following questions, a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the following choices.
(a) Assertion and Reason both are true, Reason is the correct explanation of Assertion.
(b) Assertion and Reason both are true but Reason is not the correct explanation of Assertion.
(c) Assertion is true, Reason is false.
(d) Assertion is false, Reason is true.

Assertion (A): Toxic metal ions are removed by the chelating ligands. Reason (R): Chelate complexes tend to be more stable.

Q 12.

Match the complex species given in Column I with the possible isomerism given in Column II and assign the correct code:
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-32

Q 13.

Indicate the complex ion which shows geometrical isomerism.
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-8

Q 14.

A complex of the type [M(AA)2X2]n+ is known to be optically active. What does this indicate about the structure of the complex? Give one example of such complex.

Q 15.

What is the relationship between observed colour of the complex and the wavelength of light absorbed by the complex?

Q 16.

Why do compounds having similar geometry have different magnetic moment?

Q 17.

Explain on the basis of valence bond theory that  [Ni(CN)4]2-  ion with square planar structure is diamagnetic and the[Ni(CN)4]2- ion with tetrahedral geometry is paramagnetic.

Q 18.

[Fe(H2O)6]3+is strongly paramagnetic whereas  [Fe(CN)6]3-is weakly paramagnetic. Explain.

Q 19.

How many ions are produced from the complex Co(NH3)6Cl2 in solution?
(i) 6
(ii) 4
(iii)3
(iv)2

Q 20.

Write the IUPAC names of the following coordination compounds:
(i)[Co(NH3)6]Cl3
(ii)[Co(NH3)5Cl]Cl2
(iii)K3[Fe(CN)6l
(iv)K3lFe(C2O4)3]
(v)K2[PdCl4]
(vi)[Pt(NH3)2Cl(NH2CH3)]Cl

Q 21.

Explain the bonding in coordination compounds in terms of Werner's postulates.

Q 22.

Assertion (A): Linkage isomerism arises in coordination compounds containing ambidentate ligand.
Reason (R): Ambidentate ligand has two different donor atoms.

Q 23.

What is the coordination entity formed when excess of aqueons KCN is added to an aqueous solution of copper sulphate? Why is it that no precipitate of copper sulphide is obtained when H2S (g) is passed through this solution?

Q 24.

Why do compounds having similar geometry have different magnetic moment?

Q 25.

Match the coordination compounds given in Column I with the central metal atoms given in Column II and assign the correct code:
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-27
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-28

Q 26.

Explain with two examples each of the following: coordination entity, ligand, coordination number, coordination polyhedron, homoleptic and heteroleptic.

Q 27.

Draw figure to show the splitting of d-orbitals in an octahedral crystal field.

Q 28.

What will be the correct order for the wavelengths of absorption in the visible region for the following:[Ni(NO2)6]4-, [Ni(NH3)6]2+, [Ni(H20)6]2+?

Q 29.

Give the electronic configuration of the following complexes on the basis of crystal field splitting theory.
[COF6]3-, [Fe(CN)6]4- and [Cu(NH3)6]2+.

Q 30.

CUSO4.5H2O is blue in colour while CuSO4 is colourless. Why?

Q 31.

Write the formulas for the following coordination compounds:
(i)Tetraamminediaquacobalt(IlI) chloride
(ii)Potassium tetracyanidonickelate(II)
(iii)Tris(ethanp-1,2-diamine) chromium(III) chloride
(iv)Amminebromidochloridonitrito-N- platinatc(II)
(v)Dichloridobis(ethane-l ,2-diamine) platinum (IV) nitrate
(vi)Iron(III)hexacyanidoferrate(II)

Q 32.

[NiCl4]2- is paramagnetic while [Ni(CO)4]  is diamagnetic though both are tetrahedraL Why?

Q 33.

What is crystal field splitting energy? How does the magnitude of Δ0 decide the actual configuration of d-orbitals in a coordination entity?

Q 34.

Identify the correct statements for the behaviour of ethane-1, 2-diamine as a ligand.
(a) It is a neutral ligand (b) It is a didentate ligand
(c) It is a chelating ligand (d) It is a unidentate ligand

Q 35.

A coordination compound CrCl3.4H2O precipitates silver chloride when treated with silver nitrate. The molar conductance of its solution corresponds to a total of two ions. Write structural formula of the compound and name it.

Q 36.

Why are low spin tetrahedral complexes not formed?

Q 37.

Using IUPAC norms write the systematic names of the following:
(i) [Co(NH3)6]CI3,
(ii)[Pt(NH3)2CI (NH2CH3)] Cl
(iii) [Ti(H20)6]3+
(iv) [Co(NH3)4Cl(N02)]CI
(v)|Mn(H20)6]2+
(vi)[NiCl4]2-
(vii)[Ni(NH3)6]CI2
(viii)[Co(en)3]3+
(ix) [Ni(CO)4]

Q 38.

Discuss the nature of bonding in metal carbonyls.

Q 39.

Discuss briefly giving an example in each case the role of coordination compounds in:(i)biological systems (iii) analytical chemistry (ii)medicinal chemistry and (iv) extraction/ metallurgy of metals.

Q 40.

The oxidation number of cobalt in K[Co(CO)4] is
(i)+1
(ii)+3
(iii)-1
(iv)-3

Q 41.

The colour of the coordination compounds depends on the crystal field splitting. What will be the correct order of absorption of wavelength of
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-3

Q 42.

An aqueous pink solution of cobalt (II).chloride changes to deep biue on addition of excess of HCl. This is because
(a) [Co(H2O)6]2+ is transformed into [CoCl6]4-
(b) [CO(H2O)6]2+ is transformed into [COCl4]2-
(c) tetrahedral complexes have smaller crystal field splitting than octahedral complexes
(d) tetrahedral complexes have larger crystal field splitting than octahedral complex

Q 43.

Arrange the following complexes in the increasing order of conductivity of their solution:
[Co(NH3)3Cl3], [CO(NH3)4Cl2]Cl, [CO(NH3)6]C13, [Cr(NH3)5Cl]Cl2

Q 44.

Draw all the isomers (geometrical and optical) of
(i)[CoCl2(en)2]+
(ii)[Co(NH3) Cl (en)2]2+
(iii) [Co(NH3)2Cl2(en)]+

Q 45.

Amongst the following, the most stable complex is:
(i) [Fe(H2O)6] (ii) [Fe(NH3)6]3+
(iii) [Fe(C2O4)3]3- (iv) [FeCl6]3-

Q 46.

Name the type of isomerism when ambidentate ligands are attached to central metal ion. Give two examples of ambidentate ligands.

Q 47.

CoSO4Cl.5NH3 exists in two isomeric forms ‘A' and ‘B'. Isomer ‘A' reacts with AgNO3 to give white precipitate, but does not react with BaCl2. Isomer ‘B' gives white precipitate with BaCl2 but does not react with AgNO3. Answer the following questions.
(i) Identify A' and B' and write their structural formulas.
(ii) Name the type of isomerism involved.
(iii) Give the IUPAC name of A' and B'.

Q 48.

Why are different colours observed in octahedral and tetrahedral complexes for the same metal and same ligands?

Q 49.

Give evidence that  [Co(NH3)5Cl]S04  and [Co(NH3)5S04]Cl  are ionisation isomers.

Q 50.

Predict the number of unpaired electrons in the square planar [Pt(CN)4]2- ion.